A color diffusion transfer photographic method using image-forming substances which give dyes different from image-forming substances themselves in diffusibility as a result of development under basic conditions has hitherto been well known, and as such image-forming substances (i.e., dye image-forming substances, dye-providing substances, dye-releasing compounds, image-forming compounds and dye image-forming compounds), the compounds disclosed in JP-A-59-114540 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") and JP-A-60-79353 are known.
However, many of the ages released from these dye-releasing compounds remain in photographic units other than an image-receiving layer after image formation, and they are gradually diffused into an image-receiving layer and mordanted with the lapse of time to make image density higher (hereinafter referred to as post transfer) and also there arises a problem of photographic capability such that the sharpness is deteriorated.
This tendency is still conspicuous in the mode of usage of increasing neutralization timing. Therefore, the development of techniques for improving post transfer and sharpness has been strongly desired.